The Permanent Portfolio was proposed by Harry Browne in the book Fail Safe Investing.  An excellent modern guide is The Permanent Portfolio: Harry Browne’s Long-Term Investment Strategy by Craig Rowland and J. M. Lawson.

Asset Allocation

Localized portfolio versions are organized by home country

		CAN	GER	UK	USA
25%	Total Stock Market	CAN-TSM	GER-TSM	UK-TSM	USA-TSM
25%	Long Term Bonds	CAN-LT	GER-LT	UK-LT	USA-LT
25%	Cash	CAN-BIL	GER-BIL	UK-BIL	USA-BIL
25%	Gold	GLD	GLD	GLD	GLD

Study your own interpretation with the My Portfolio tool

Performance

Change the home country to translate the portfolio to local assets, currency, and inflation